1. Field of the Invention
This invention relates to process for consecutive, competitive gas phase halogenation of gaseous aliphatic and aromatic hydrocarbons of no more than 12 and 9 carbon atoms, respectively and their partially reacted intermediates. More specifically, it relates to a process for the suppression of partially substituted intermediates in consecutive-competitive gas phase reactions to produce various commercially desirable halogenated derivatives, economically and in high yield.
2. Description of the Prior Art
Halogenated derivatives of hydrocarbons are widely employed in the industry in a variety of applications, including such uses as solvents and intermediates in the production of refrigerants and other chemicals. However, production of these halogenated derivatives from hydrocarbons, their partially halogenated derivatives and mixtures thereof by first order, consecutive-competitive reactions with a gaseous halogen is complicated by the formation of undesired by-products, e.g. partially halogenated intermediates. When tubular flow and back-mix reactors are employed in the chlorination of methane and partially-chlorinated derivatives thereof, relatively high amounts of undesired partially-chlorinated by-products have been found to be produced at the expense of the desired carbon tetrachloride. In the chlorination of ethane and partially-chlorinated ethanes, relatively high amounts of undesired chloroethanes have been found to be produced at the expense of the desired chloroethylenes. Moreover, since these chlorination reactions are exothermic, conventional reactors are disadvantaged by the practical limits placed on the rate of chlorine fed to the reactor due to difficulty in removing the heat of reaction and, hence, in controlling the reaction temperature. Excessively high temperatures are not desired because they result in formation of large amounts of carbon, due to pyrolysis of the hydrocarbon feed, which fouls the reactor and downstream equipment. Thus, the prior art has typically employed staged reactions (to provide incremental reaction of the hydrocarbon and chlorine), with intermediate cooling or with extensive recycle of less highly chlorinated by-products in order to obtain the desired chlorinated hydrocarbon. Use of staged reaction methods or of extensive recycles is undesirable because of the large amount of equipment required and the consequent high cost.